1. Field of the Invention
The present invention is related to the field of munitions and, more particularly, to improved munitions design reflective casing constructions for solid explosive munitions demonstrating improved performance characteristics.
2. Description of the Related Art
Historically, the radiation that accompanies chemical reactions, such as the detonation of high energy explosive munitions, has been treated as an incidental, minor release of energy. Furthermore, explosive munitions have traditionally been made using highly absorbing, low reflecting materials such as tar, asphalt-like substances or black polymers to line the casings and cushion the munition.
It is known that high energy devices that vary in their casing size and material composition have different performance characteristics. FIG. 1, taken from the Design and Analysis of Hardened Structures (DAHS) Manual for case charges, summarizes prior art experimental evidence in which test results obtained for different casing materials were evaluated in terms of Equivalent Mass Ratio (EMR). Equivalent mass ratio is defined as W′ divided by W, where W is the amount of explosive, such as TNT, in an encased sample and producing a given blast effect, and W′ is that corresponding amount of TNT which would be required to produce the same blast effect in an open air detonation, i.e., without a casing.
In FIG. 1, relative performance in terms of the equivalent mass ratio is plotted as a function of the ratio of the casing mass, mc, to the charge mass, W. As shown, different casing materials yield different equivalent mass ratios, because different casing materials enhance the explosive effect of the encased explosive (e.g., TNT) to differing degrees over the bare charge performance of EMR=1.
The data presented in FIG. 1 illustrates that for steel, the equivalent mass ratio decreases with increased case mass relative to the charge mass, whereas for the other materials tested there is a substantial increase in EMR, with each material reaching a different maximum value. Aluminum, for example, demonstrates an enhancement of more than 100% over the steel casing performance at a case mass/charge mass ratio that is greater than unity. However, as the basis for these differences in performance enhancement had not been fully understood, it was difficult or impossible to utilize these observed enhancements in the design of explosive munitions. Consequently, they have for the most part been ignored or discounted in all of the past and current designs of munitions to accomplish selected tasks.